This invention relates generally to surgically implantable devices utilized to access selected portions of a body. More specifically, the present invention relates to implantable devices utilized to access a body cavity resulting from removal of a tumor or the like, which devices permit fluid access to the cavity at an injection site remote from a cavity wall aperture.
Many medical devices have been developed to provide access to selected body parts or systems. Some such devices are subcutaneously implantable and are controlled by percutaneous manipulation. Exemplary of such percutaneously manipulable devices are a broad family of cerebrospinal fluid shunts, one of which is illustrated in U.S. Pat. No. 4,552,553. Other subcutaneously implantable medical devices are utilized to direct medication to a particular portion of the body, wherein the medication is injected at a site remote from the delivery location. Exemplary of such devices are the subcutaneous infusion reservoir and pump systems found in U.S. Pat. Nos. 4,816,016; 4,761,158; 4,681,560 and 4,588,394.
In many infusion reservoir and pump systems, which may be utilized to direct a powerful pain killing drug such as morphine to the central nervous system on demand, a variable capacity reservoir is connected by tubing or the like to an injection port which receives medication by injection. The reservoir receives and stores fluid medication for delivery to a catheter which directs the medication to a specific infusion location in the body. Typically, a control assembly is interposed between the reservoir and the catheter to facilitate and control the transfer of the medication from the reservoir to the catheter in a safe and efficient manner. The control assembly is constructed to prevent the backflow of fluid from the catheter to the reservoir, as well as the unrestricted flow of medication through the control assembly.
In the treatment of cancer, physicians now have a wide variety of treatment methods which are useful in reducing the extent of the disease and, sometimes, in eradicating the disease from the patient. Such treatment methods include radiation therapy, chemotherapy, excision of the cancerous growth from the body, and often a combination of these alternatives. Intratumor cyst implants have been developed for the treatment of malignant gliomas of the nervous system in response to the need for reliable indices of tumor response to therapy, and access of sytotoxic agents to unresectable portions of the glioma. In such intratumor cyst implants, a prosthesis is implanted within the center of the glioma after surgical resection of a suitable core, or within the raw surfaces of the residual tumor if an extensive lobectomy is feasible. Samples of tumor extracellular fluid and tumor cells can be withdrawn at frequent intervals and medication injected repeatedly by the reservoir connected to the cyst implant. The reservoir provides an injection site remotely situated from the cyst implant. Prior intratumor cyst implant devices are not satisfactory, however, in many instances.
By way of example, after all or part of a cancerous growth has been excised from the body, it is often desirable to utilize chemotherapy medications or killer "T" cells to kill any remaining cancer cells lining the body cavity created by the excision. Prior intratumor cyst implants do not optimally lend themselves to such treatment since a cavity wall aperture must be quite large to permit the implant to be removed following treatment, or a second surgical procedure is required to remove the same from the cavity. Further, due to the inflexible nature of the implant, a large quantity of medication must be injected into the remote injection site for delivery, through a catheter or the like, to the cavity in order to fill a void defined by the cavity walls and ensure that adequate treatment is effected on the cavity walls.
Accordingly, there has been a need for a novel tumor access device which is completely subcutaneously implantable, of simple construction, and accessible through the skin of the patient by injection. Such a device should be insertable through a relatively small cavity wall aperture, be capable of substantially filling the void therein, and require a minimum quantity of medication for effective treatment of the tissue surrounding the cavity. Further, a tumor access device is needed which minimizes any surgical procedure required to remove the device from the body, and whose configuration within the patient is adjustable and can be detected through x-ray photography. Finally, there exists a significant need for a novel treatment method for accessing a body cavity through a relatively small cavity wall aperture, and for delivering medication into the body cavity. The present invention fulfills these needs and provides other related advantages.